I wasn't sure whether to put this in the mechanical engineering board or not but since electrical engineers typically design electric motors, I'll put it here. From what I hear, all types of electric motors have terrible power-to-weight ratios. So if we were to hypothetically one day have a light-weight battery with the energy density of jet fuel, we wouldn't be able to have an electric 747 because an electric motor with enough power to lift a 747 would be too heavy. So I was wondering, how would you go about trying to increase the power-to-weight ratio of an electric motor? Are there any institutions doing research on this? Note: I suppose we wouldn't need batteries to have an energy density as high as that of jet fuel since an electric 747 engine would be a lot more efficient than the combustion version but you get my point.